... but what if in your spiritual development you ran across something that falls outside the realm of traditional thinking?
Depends.
I'm Catholic. If I ran across something that falls outside the Tradition, then I would be skeptical. I would look to its provenance, ask for 'evidence', for a reasoned and logical argument in support. If it was something that as a Catholic I should believe or do, but something 'not contained in scripture. Perhaps even appearing to go against it' then I would be doubly-cautious. Again, I'd look for its source and origin, and look for commentaries that touch on it.
Take reincarnation. It's not mentioned in Scripture, so that's strike one. It's not mentioned
at all in the commentaries of the Tradition, strike two. Logically, its incompatible with the Tradition's idea of the 'person', strike three. (Some might argue Origen on metempsychosis, but that's too detailed to go into here.) There are those who cite a couple of texts in support of the idea, but they do so out of context, and dismiss the traditional interpretation of the text without reason. Their bias is clear, and I'm afraid that stands against them.
If however, I ran across something outside Christianity as such, say Buddhism or the Dao, and that 'spoke to me', then there we have a case of conversion, a kind of 'Damascus moment'. Then I could not say what might happen ...
I did try 'converting' to Zen at one point, but it was never authentic, it was a change of mind, but not a change of heart.
Unless that is, I had come to a realization on my own by way of first hand experience.
Well first hand experience is the most fallible and least reliable data of the lot ... and we have to distinguish between what kind of experience we're talking about.
Take empirical/physical experience, and put that on one side. We're talking a different order of thing altogether.
Take 'the zone' ... you know that place athletes talk about, say long distance runners? It sounds cool, and I want to 'get into the zone'. How do I do it? As the old adage has it, practice, practice and more practice. And even then, it's not guaranteed. In short, hard work. Now there are those who ill say, 'you know what it's like when... ' and offer an analogy. OK. But an analogy is not the zone, but people assume that because they felt something like it, they were in the zone ...
The classic distinction is between spirit and Spirit, between intellectual light and Enlightenment, between knowing and being. The latter is a whole different order of thing, but many assume that the two are near enough the same. So some have first hand experience of the former, and tell themselves it's the latter, and when anyone suggests they're wrong, then they get a swift rebuttal. I'm right? How do I know, because I know! If 'tradition' says otherwise, then the tradition is wrong.
The classic argument: What I believe is right, and right for me, because I believe it.